BOSTON – Mixed martial arts can be a lot like the weather in New England. If you don't like who's on top, wait a little while and it's likely to change.

Frank Edgar established himself – for the time being – as one of the sport's superstars with a one-sided mauling of former champion B.J. Penn in the main event of UFC 118 Saturday at TD Garden.

Edgar lifted the lightweight title from Penn at UFC 112 in Abu Dhabi, United Arab Emirates, via an agonizingly close decision. There was nothing controversial about Saturday's outcome as Edgar battered Penn around the cage as if Penn, not boxer James Toney, were making his mixed martial arts debut.

Penn is one of the greats in the history of the sport, but Edgar has firmly established himself as one of the sport's active greats. Forget the moronic notion that he should abandon the 155-pound division to compete in World Extreme Cagefighting as a 145-pounder. The next person who asks that should be institutionalized.

All three judges scored the bout 50-45, but even the shutout didn't really indicate Edgar's dominance. Edgar outlanded Penn 155-53, but it was even more telling over the final three rounds, when Edgar stepped on the gas pedal and Penn had no answer. In Rounds 3-5, Edgar outlanded Penn 119-23.

After manhandling Penn for 25 minutes Saturday, it was hard to do anything other than to say, "Wow."

"He absolutely dominated B.J. Penn everywhere in the Octagon tonight," Ultimate Fighting Championship president Dana White said. "On his feet, on the ground, wrestling. The first couple of times he took (Penn down), I couldn't believe it. And not only did he take him down, he was going down hard. He put on an incredibly dominant performance tonight against a guy who has been the best in the world for a long time."

Edgar has proven himself the equal of the four other men he shares a UFC championship belt with: heavyweight Brock Lesnar, light heavyweight Mauricio "Shogun" Rua, middleweight Anderson Silva and welterweight Georges St. Pierre.

He hasn't gotten much respect, despite entering the fight with a 12-1 MMA record and a 7-1 UFC mark. He's quietly gone about his business and has routinely put on some of the UFC's most exciting fights and never complained when he wasn't singled out.

He noted that most fighters compete with a chip on their shoulder, but the one on Edgar's has to be the size of a boulder. He fights like he has something to prove every second of every match, though that's usually because he does.

Penn once again failed to show for the postfight news conference, but he didn't have to say much. The result of the fight said all that needed to be said.

"Frankie fought a great fight," Penn said in the cage following his second consecutive loss and his third in his last five outings. "He's the man. I have nothing bad to say."

If he had, he would have looked stupid. Edgar was magnificent and, at 28, clearly getting better. He'll get a chance to avenge his only loss, an April 2008 defeat at the hands of Gray Maynard, who earlier on Saturday routed Kenny Florian to set up the rematch.

Maynard manhandled Edgar in that fight, but Edgar has improved so much in the five fights he's had since that Maynard won't be facing anywhere near the same person.

"I believe in myself, my team believes in me and if it takes time for you guys [in the media] to believe in me, I know I'll do that, too," Edgar said.

He started quickly and ended strong. He outboxed Penn. He took Penn to the ground four times – though Penn has arguably the sport's best takedown defense. And he seemed to even outgrapple the jiu-jitsu wizard on the ground. Anything a mixed martial artist would need to do, Edgar did on Saturday.

"He's changed a lot," Maynard said of Edgar. "Our fight was what, two and a half, three years ago. He has changed a great deal. He's not the same fighter."

Penn isn't either. Two losses in a row and three in his last five don't signal that he's on the verge of being finished, but he's got plenty of soul searching to do. There are times he appears like he's among the handful of the greatest fighters who ever lived, but more recently, he looks lost.

White isn't sure what to do with him and Penn, in the cage after the loss, conceded he has to go home and mull over his future.

There are no such problems with Edgar. If he gets by Maynard, there is George Sotiropoulos on the horizon, as well as a legion of other top contenders.

MMA is about as humbling a sport as golf. Fighters who are on top and look invincible one night often appear vulnerable and confused the next time out. It's the nature of the beast.

Edgar is young and a pro for just under five years. He appears to be a guy still on the rise.

"I built on my confidence [from the first Penn fight]," Edgar said. "The first time I was in there, I had the confidence I could do what I needed to do, but I hadn't done it before. After doing it and knowing I could do it going in a second time, that confidence added a lot to it."

Maynard may be the guy who knocks Edgar off his lofty perch. Perhaps it will be Sotiropoulos or even Jose Aldo, the WEC featherweight champion who may eventually jump to lightweight.

Sooner or later, Edgar's going to be throttled the way he throttled Penn. The person who is the one who ultimately does it remains a mystery.

But we already know this much about that guy: If he's going to beat Frank Edgar and win the UFC lightweight championship, he's going to be one damn good fighter.